The number of amputees in the world has risen significantly in recent years, with war injuries and dysvascular diseases such as diabetes accounting for approximately 90% of all amputee cases. There are currently about 1.7 million amputees living in the United States alone, and approximately 135,000 new amputee patients are discharged annually from hospitals. Further, it has been estimated that there will be a 20% increase in the number of new amputee cases per year by 2050.
Unfortunately, due to persistent pain in limb remnants, about 25% of amputees are not able to commence rehabilitation, much less resume ordinary daily activities. The cause of such pain can be a neuroma. One recent study reported that 78% of amputees experienced mild to severe pain as a consequence of neuroma formation over the 25-year study period, of which 63% described the pain as constant aching pain. The pain is also frequently described as sharp, shooting, or electrical-like phantom sensations that persist for years after surgical amputation. In addition, patients experience tenderness to palpation of the skin overlying the neuroma, spontaneous burning pain, allodynia, and hyperalgesia.
Neuromas are benign tumors that arise from neural tissue and are composed of abnormally sprouting axons, Schwann cells, and connective tissue. Even though neuromas can appear following various types of injuries, some of the most common and challenging to treat are derived from amputation surgeries in which neural tissue is sectioned by retraction axotomy. The lack of organ-target acquisition by the resulting nerve stump results in a subsequent cascade of biological events that culminate in the formation of a neural nodule.
To treat patients with painful neuromas, doctors have relied on multiple treatment modalities. However, many existing treatment modalities have a high recurrence rate, address the problem only after it has established itself in the patient, and/or are not definitive. A high neuroma recurrence rate can lead to repeated surgical resections. Further, the prevention of neuroma formation by some prior methods has also proven unsatisfactory, sometimes requiring multiple procedures. Therefore, there exists a need for improved devices and methods for the prevention and treatment of neuromas.